Chemical-biological Oxidation Process For Treating Cellulosic Ethanol Production Wastewater

An efficient treatment technology of wastewater from cellulose ethanol production was studied.Based on the comprehensive analysis of wastewater,Fenton oxidation pretreatment,anaerobic and aerobic biological treatment,Fenton oxidation and activated carbon adsorption posttreatment were used,providing technical support for the design of cellulosic ethanol wastewater treatment process.According to wastewater quality analysis results,COD was 24000~27000 mg/L,BOD was 5000~6000 mg/L,B/C of the wastewater was about 0.22.Wastewater contains 38 kinds of organic substances,including toxic substances such as phenol,dioxane and furfuralcohol.Wastewater was high concentrated and was difficult to be biodegradable.After Fenton oxidation pretreatment COD removal rate was 31% and TOC removal rate was 18%,B/C increased from 0.22 to 0.54,biological toxicity decreased by 54%,and biodegradability was greatly improved.After hydrothermal Fenton oxidation pretreatment COD removal rate was 40%,biological toxicity decreased by 27%,color increased by 80%.Hydrothermal Fenton oxidation pretreatment effectively reduced the COD and biological toxicity.A batch experiment was carried out to treat the Fenton pretreatment effluent by anaerobic and aerobic biological treatment.COD of anaerobic reactor influent was 8655 mg/L,effluent COD was reduced to 1770 mg/L,aerobic biological treatment effluent COD was 519 mg/L,and the overall COD removal rate was more than 94%.The results of Fenton oxidation and activated carbon adsorption treatment showed that,Fenton oxidation treatment achieved 61% COD removal rate and 80% color removal rate,and activated carbon adsorption treatment achieved 60% COD removal rate and 83% color removal rate.After Fenton oxidation and activated carbon adsorption treatment,COD and color were lower than 100 mg/L and 10 times.